资 源 简 介
The MC34673 is a cost-effecTIve fully-integrated battery charger forLi-Ion or Li-Polymer batteries. The high input voltage, up to 28V,eliminates the input over-voltage protecTIon circuit required in handhelddevices such as PDAs, cell phones, portable video game players anddigital sTIll cameras.A typical charge cycle includes trickle, constant-current (CC) andconstant-voltage (CV) charge modes. The CC-mode current isprogrammable up to 1.2A with an external resistor. The voltage acrossthe external resistor is also used to monitor the actual charge current.The constant voltage is fixed at 4.2V with 0.7% accuracy over a -20°Cto 70°C temperature range. The trickle-mode current is preset to 20%of the CC-mode current when the battery voltage is lower than thetrickle-mode threshold. The end-of-charge (EOC) current threshold ispreset to 10% of the CC-mode current to save the board space andcost. A charge current thermal foldback feature limits the chargecurrent when the IC internal temperature rises to a preset threshold.The MC34673 also protects the system with its input over-voltageprotecTIon (OVP) feature. In addition, the MC34673 has a 2.6V fallingpower-on-reset (POR) threshold, making it perfect to work with currentlimited power supplies. Three indication pins (PPR, CHG and FAST)can be simply interfaced to a microprocessor or LEDs. When no powersupply is connected, or when disabled, the charger draws less than1.0μA leakage current from the battery.
